Mayer, R. E. (2004). Should there be a three-strikes rule against pure discovery learning? The case for guided methods of instruction. American Psychologist, 59(1), 14–19. https://doi.org/10.1037/0003-066X.59.1.14

Seidel, T., & Scheerens, J. (2005). Towards a research review and meta-analysis on teaching and learning: Preliminary results and proposed next steps. Paper for the joint Network A and C Task Force on Teaching Effectiveness of OECD INES, Reykjavik, October 8–9, 2005.